Amane Kozuki

Natural consequence of post-intervention stent malapposition, thrombus, tissue prolapse, and dissection assessed by optical coherence tomography at mid-term follow-up

Aims We performed this study to clarify natural consequences of abnormal structures (stent malapposition, thrombus, tissue prolapse, and stent edge dissection) after percutaneous coronary intervention (PCI). Methods and results Thirty-five patients treated with 40 drug-eluting stents underwent serial optical coherence tomography (OCT) imaging immediately after PCI and at the 8-month follow-up. Among a total of 73 929 struts in every frame, 431 struts (26 stents) showed malapposition immediately after PCI. Among these, 49 remained malapposed at the follow-up examination. The mean distance between the strut and vessel wall (S–V distance) of persistent malapposed struts on post-stenting OCT images was significantly longer than that of resolved malapposed struts (342 ± 99 vs. 210 ± 49 μm; P <0.01). Based on receiver-operating characteristic curve analysis, an S–V distance ≤260 µm on post-stenting OCT images was the corresponding cut-off point for resolved malapposed struts (sensitivity: 89.3%, specificity: 83.7%, area under the curve = 0.884). Additionally, 108 newly appearing malapposed struts were observed on follow-up OCT, probably due to thrombus dissolution or plaque regression. Thrombus was observed in 15 stents post-PCI. Serial OCT analysis revealed persistent thrombus in 1 stent, resolved thrombus in 14 stents, and late-acquired thrombus in 8 stents. Tissue prolapse observed in 38 stents had disappeared at the follow-up. All eight stent edge dissections were repaired at the follow-up. Conclusion Most cases of stent malapposition with a short S–V distance, thrombus, tissue prolapse, or minor stent edge dissection improved during the follow-up. These OCT-detected minor abnormalities may not require additional treatment.

Optical coherence evaluation of everolimus-eluting stents 8 months after implantation

Objective The aim of this study was to evaluate detailed vessel response after everolimus-eluting stents (EES) implantation in human de novo coronary lesions by optical coherence tomography (OCT). Design, setting and patients Between November 2008 and October 2009, 25 patients (14 men, 65.5±8.6 years) with de novo native coronary artery lesions were implanted with 30 EES, and OCT was performed at 8 months post-implantation. Main outcome measures Neointimal thickness (NIT) on each strut, strut apposition to the vessel wall, the frequency of struts surrounded by low intensity area and the incidence of intra-stent thrombus were analysed. To evaluate the radial unevenness of NIT, the difference between the maximum and minimum NIT (dNT) was calculated for each cross-section. Results At 236±39 days after implantation, there were no major adverse cardiac events, nor target vessel revascularisation. A total of 5931 struts was evaluated by OCT. The median NIT was 80 μm (25th and 75th percentile 50 μm and 140 μm) and average NIT was 100±74 μm. The number of neointima-covered struts was 5834 (98.4%), and 31 (0.52%) struts showed malapposition without neointimal coverage. The number of struts surrounded by low intensity area was 452 (7.62%). Eleven EES (37%) showed full neointimal coverage. No intra-stent thrombus was detected. The average dNT was 108±77 μm. Conclusions Most EES struts were covered with uniform and thin neointima. The frequency of low-intensity neointima was very low, which may be a result of promoted vessel healing. These results may support improved clinical outcomes with EES in clinical trials.

Stabilizing effect of combined eicosapentaenoic acid and statin therapy on coronary thin-cap fibroatheroma

BACKGROUND The addition of highly purified eicosapentaenoic acid (EPA) to statin therapy prevents cardiovascular events. However, the impact of this treatment on vulnerable plaques remains unclear. The aim of this study was to assess the impact of adding EPA to a standard statin therapy on vulnerable plaques by serial optical coherence tomography (OCT). METHODS Forty-nine non-culprit thin-cap fibroatheroma (TCFA) lesions in 30 patients with untreated dyslipidemia were included. Patients were randomly assigned to EPA (1800 mg/day) + statin (23 TCFA, 15 patients) or statin only (26 TCFA, 15 patients) treatment. The statin (rosuvastatin) dose was adjusted to achieve a target low-density lipoprotein (LDL) level of <70 mg/dL. Post-percutaneous intervention and 9-month follow-up OCT were performed to evaluate morphological changes of TCFAs. The EPA/arachidonic acid (EPA/AA) ratio and pentraxin-3 (PTX3) levels were also evaluated. RESULTS Despite similar follow-up LDL levels, the EPA + statin group had higher EPA/AA ratios and lower PTX3 levels than the statin group. OCT analysis showed that the EPA + statin group had a greater increase in fibrous-cap thickness, with a greater decrease in lipid arc and lipid length. Macrophage accumulation was less frequently detected in the EPA + statin group than in the statin group at follow-up. When the patients were categorized according to their follow-up PTX3 tertiles, fibrous-cap thickness showed significant increase, and the incidence of macrophages accumulation decreased with lower PTX3 levels. CONCLUSION The concomitant use of EPA and rosuvastatin may stabilize vulnerable plaques better than the statin alone, possibly by suppressing arterial inflammation.

Analysis by Optical Coherence Tomography of Long-term Arterial Healing After Implantation of Different Types of Stents

BACKGROUND Although drug-eluting stents have significantly reduced the midterm incidence of target lesion revascularization (TLR), in vivo studies on long-term vessel healing of sirolimus-eluting stents (SESs) and paclitaxel-eluting stents (PESs) are limited. The aim of this study was to compare long-term arterial healing with SESs and PESs. METHODS We evaluated 27 SESs (23 patients) and 21 PESs (20 patients) by serial optical coherence tomography at 6 months (midphase) and ≥ 3 years (late phase) after stenting and evaluated the change of neointimal thickness (NIT), the percentages of uncovered and malapposed struts, peristrut low-intensity area (region around stent struts with a homogeneously lower intensity appearance than surrounding tissue), thrombus, and atherogenic neointima. RESULTS At follow-up, most SESs showed a progressive increase in the average NIT, whereas PESs showed variable changes. Between midphase and late phase, NIT increased significantly in SESs (midphase, 94.1 ± 49.3; late phase, 130.2 ± 78.7; P = 0.001) but decreased significantly in PESs (midphase, 167.4 ± 122.9; late phase, 136.0 ± 77.7; P = 0.04). The percentages of uncovered struts decreased significantly in SESs; conversely, variable changes were observed in PESs. Peristrut low-intensity area and thrombus formation decreased in SESs but remained largely unchanged in PESs. The prevalence of atherogenic neointima was greater in the late phase than in the midphase in both groups but was similar for both stents. CONCLUSIONS Long-term vessel healing was different for SESs and PESs. Progressive vessel healing was consistently observed in SESs, whereas a heterogeneous process of delayed vessel healing was noted for PESs.

Optical coherence tomography study of chronic-phase vessel healing after implantation of bare metal and paclitaxel-eluting self-expanding nitinol stents in the superficial femoral artery.

BACKGROUND This study aimed to assess chronic-phase suppression of neointimal proliferation and arterial healing following paclitaxel-coated (PTX) and bare metal stent (BMS) implantation in the superficial femoral artery using optical coherence tomography (OCT). METHODS Twenty-five patients with 68 stents underwent an 8-month OCT follow-up. Besides standard OCT variables, neointimal characterization and frequencies of peri-strut low-intensity area (PLIA), macrophage accumulation, and in-stent thrombi were evaluated. RESULTS The mean neointimal thickness was significantly less with PTX stents (544.9±202.2 μm vs. 865.0±230.6 μm, p<0.0001). The covered and uncovered strut frequencies were significantly smaller and larger, respectively, in the PTX stent group vs. the BMS group (93.7% vs. 99.4%; p<0.0001, 4.0% vs. 0.4%; p<0.0001, respectively). Heterogeneous neointima was only observed in the PTX stent group (12.5% vs. 0%, p=0.017). The frequencies of PLIA and macrophage accumulation were significantly greater in the PTX stent group (87.2% vs. 67.6%, p=0.001 and 46% vs. 9.1%, p=0.003, respectively). CONCLUSION After 8 months, reduced neointimal proliferation was observed with PTX stent implantation. On the other hand, delayed arterial healing was observed compared with BMS.

Feasibility of a novel radiofrequency signal analysis for in-vivo plaque characterization in humans: Comparison of plaque components between patients with and without acute coronary syndrome

BACKGROUND The iMAP™ is a novel intravascular ultrasound (IVUS)-based technology to classify coronary plaque into 4 components. The aim of this study was to evaluate the feasibility of iMAP™ technology by comparing plaque characteristics in patients with and without acute coronary syndrome (ACS and non-ACS). MATERIALS AND METHODS A total of 93 culprit lesions from 87 patients were analyzed using the iMAP™. Each plaque was classified into 4 components with a newly introduced parameter, confidence level (CL). RESULTS iMAP™ analysis of the minimal lumen cross-sectional area (MLA) revealed that ACS lesions had significantly larger lipidic and necrotic areas than non-ACS lesions. Multivariate analysis revealed that the lipidic area at the MLA was an iMAP™ factor independently associated with ACS lesions (odds ratio -1.5, p=0.04). Based on receiver operating characteristic analysis with 4 different CL ranges, the lipidic area at the MLA with 25%-100% CL had the largest area under the curve (0.756), suggesting that 25%-100% is the best CL range for identifying ACS culprit lesions. CONCLUSIONS The feasibility of the novel iMAP™ IVUS system was shown in discriminating culprit lesions in patients with and without ACS. Analyzing with a CL of 25%-100% may be the best option for discriminating lesions.

Temporal Course of Vessel Healing and Neoatherosclerosis After DES Implantation

Recently, late drug-eluting stent (DES) failure has become a potential cause for concern following first-generation DES implantation. Although these phenomena may result from multiple etiologic factors, emerging evidence consistently suggests the importance of delayed arterial healing and

Reduction in coronary microvascular resistance through cardiac resynchronization and its impact on chronic reverse remodelling of left ventricle in patients with non-ischaemic cardiomyopathy

AIMS Left bundle branch block (LBBB) induces mechanical dyssynchrony, thereby compromising the coronary circulation in non-ischaemic cardiomyopathy. We sought to examine the effects of cardiac resynchronization therapy (CRT) on coronary flow dynamics and left ventricular (LV) function. METHODS AND RESULTS Twenty-two patients with non-ischaemic cardiomyopathy (New York Heart Association class, III or IV; LV ejection fraction, ≤35%; QRS duration, ≥130 ms) were enrolled. One week after implantation of the CRT device, coronary flow velocity and pressure in the left anterior descending coronary artery (LAD) and left circumflex coronary artery (LCx) were measured invasively, before and after inducing hyperemia by adenosine triphosphate administration, with two programming modes: sequential atrial and biventricular pacing (BiV) and atrial pacing in patients with LBBB or sequential atrial and right ventricular pacing in patients with complete atrioventricular block (Control). We assessed hyperemic microvascular resistance (HMR, mean distal pressure divided by hyperemic average peak velocity) and the relationship between the change in HMR and mid-term LV reverse remodelling. Hyperemic microvascular resistance was lower during BiV than during Control (LAD: 1.76 ± 0.47 vs. 1.54 ± 0.45, P < 0.001; LCx: 1.92 ± 0.42 vs. 1.73 ± 0.31, P = 0.003). The CRT-induced change in HMR of the LCx correlated with the percentage change in LV ejection fraction (R = -0.598, P = 0.011) and LV end-systolic volume (R = 0.609, P = 0.010) before and 6 months after CRT. CONCLUSION Cardiac resynchronization therapy improves coronary flow circulation by reducing microvascular resistance, which might be associated with LV reverse remodelling.

Feasibility and usefulness of three-dimensional optical coherence tomography guidance for optimal side branch treatment in coronary bifurcation stenting

BACKGROUND For the treatment of coronary bifurcation lesions, optimal guidewire (GW) recrossing after main vessel stenting is important for good stent apposition at the side branch (SB) orifice in kissing balloon inflation (KBI). METHODS We analyzed 150 bifurcation lesions treated with single stenting following KBI in the three-dimensional optical coherence tomography (3D-OCT) bifurcation registry study (2015-16) and a single center experience (2012-16). OCT examination was performed after GW recrossing to the SB and after KBI. Patients were divided into two-dimensional (2D, n=78) and 3D groups (n=72) according to 2D- or 3D-OCT guidance. GW recrossing position, jailing configuration of the stent over the SB (divided into Link-connecting type: stent link connecting to the carina and Link-free type: no stent link at the carina) and stent apposition were compared between the groups. RESULTS Distal GW recrossing was achieved in 75.6% and 91.7% in the 2D and 3D groups, respectively (P=0.004). Compared with the 2D group, the incidence of incomplete stent apposition (ISA) toward the SB in the 3D group tended to be lower in the whole cohort (14.5±13.6% vs 10.0±9.0%, P=0.077), and was significantly lower in left main trunk bifurcations (18.7±12.8% vs 10.3±8.9%, P=0.014). Independent contributors to ISA were the Link-connecting type (β 0.089, P<0.001), distal GW recrossing (β -0.078, P=0.001), and age (β -0.0020, P=0.012). CONCLUSION Optimal GW recrossing under 3D-OCT guidance is feasible and improves stent apposition, which may lead to a better clinical outcome in the treatment of bifurcation lesions.

A case of an ablation catheter entrapped in the pulmonary vein during atrial fibrillation ablation requiring open heart surgery for removal

Case Report A 64-year-old woman with a 3-year history of drug refractory paroxysmal atrial fibrillation was referred to our hospital for catheter ablation. Preprocedual echocardiography and enhanced computed tomography (CT) revealed no structural heart disease or anatomic anomalies (Figure 1A). Catheter ablation of the atrial fibrillation was performed under conscious sedation. Two 8.5-F long sheaths, an 8-F long sheath, and a 6-F short sheath were introduced percutaneously via the right femoral vein. A 6-F venous sheath was introduced via the right internal jugular vein. A decapolar electrode catheter was positioned in the right ventricular apex. A duodecapolar electrode catheter was advanced into the coronary sinus. A transseptal puncture was performed with the assistance of intracardiac echocardiography using a radiofrequency needle (Japan Lifeline, Tokyo, Japan). Three long sheaths were advanced into the left atrium through the same puncture site. Pulmonary vein (PV) and left atrial angiogram revealed no anatomic anomalies, and the sheaths were placed into the superior PVs. Two circular mapping catheters were positioned in the PVs. An ablation catheter (Thermocool Smart Touch, Biosense Webster, Diamond Bar, CA) was inserted into the 8.5-F sheath placed in the right superior PV. The ablation catheter was pulled back and moved to start the ablation. The operator intended to place the ablation catheter into the left PV and pushed the